In this map from the 1984 Presidential election, blue represented the incumbent (Ronald Reagan of the Republican Party) and red represented the challenger (Walter Mondale of the Democratic Party). This use of blue for the incumbent party and red for the challenging party was typical in electoral maps prior to the 2000 election. Via PresidentElect.org.
A recent post by Professor David G. Post at The Volokh Conspiracy started me thinking of "red states" and "blue states."
This is my memory: prior to the 2000 election, in newscasts, newspapers and all other media that I saw, blue was the color of the incumbent Party for the Presidency and red was the color of the challenging Party.
My memory of the above standard usage: blue = incumbent Party for the Presidency, red = challenger Party for the Presidency ... goes back to the early 1970's.
Thus, in the 2000 election, the Democrats (and Al Gore) were signified by blue on maps (since Bill Clinton and the Democrats were the incumbent Party holding the Presidency). The Republicans and George W. Bush were signified by red because they were the challenging Party for the Presidency.
By contrast, in 1992 Bill Clinton and the Democrats were signified by red whereas George H.W. Bush and the Republicans were signified by blue.
Then, with all the tumult around that 2000 Presidential election - and the resulting debates about the series of red-blue maps (on both the state and county level) - many people began to associate red with Republican and blue with Democrat generally.
The Democratic Party wisely ran with this.
The Republican Party foolishly did not push back against this.
It is helpful to the Democratic Party to be signified as blue and not red because:
(1) blue is a relatively calming, safe color,
(2) red is easily associated with "reds" as in communists or socialists - which strikes a bit close to home for many Democratic policies (when you get a moment sometime read the positions of the Democratic Party and then go read the positions of the Communist Party USA - you will be surprised at the many similarities), and
(3) painting the Republicans with red makes them a kind of permanent insurgent, radical party - since red is a relatively radical, aggressive, angry color (i.e., one "sees red").
The Republican Party (and conservative commentators and media) should use the traditional standard of blue = incumbent Party for the Presidency, red = challenging Party for the Presidency - which existed prior to the 2000 election.
Why they haven't - and why there's never even been an intelligent discussion of this topic (thanks for your post - it's the first I've seen anywhere on this) is a real mystery to me.
If we must forever associate each party with a color, however, the Republican Party (and conservative writers and commentators) would be foolish not to always associate the Democratic Party with the color red.
"Reds" historically referred to communists. See, e.g., here.
And the official positions of the Democratic Party and the Communist Party USA are strikingly similar. See the agenda of the Democratic Party here. Now go look at the agenda of the Communist Party USA here.
Along these lines, the Communist Party USA's glowing praise of Barack Obama is telling.
I've looked around (just a little googling) for some evidence of my strong memory of the traditional color code for maps in American Presidential elections, i.e., challenging party = red, incumbent party = blue.
So far I've come up with:
1. here (see comment 17),
2. here, and
2 years ago